animation navigation view when pushing or popping starts after some delay

I experience some performance issue for iOS within the app I currently work on. The problem occurs when certain buttons are tapped, which will push a view on the navigation stack of the navigationview component. Somehow it starts after some delay, actually too long from an user experience point of view. My question is, could this be because I use for example complex CSS3... are there any known limits for performance..? Or could it be because I have autodestroy=true for each pushed view..?

well, then what is many... I mean the view contains; an input field, 5 buttons and a list with no more then 3 items max. The buttons are however, made out of css3 purely. So rounded corners, gradient background and a webkit mask for an icon.